Carbon nanotube effect on the reverse flexoelectricity of a planar liquid crystal cell

ABSTRACT

Unique properties of carbon nanotubes (CNTs) such as high anisotropy could be utilised in liquid crystal (LC) medium and it may improve the physical properties of the host medium. In this regard, enhancement of permittivity and flexoelectric coefficients of the medium is calculated through doping an LC planer cell with single-walled carbon nanotubes (SWCNTs), here. These calculations consider the effect of the applied electric field. A splay type curvature orientation is induced in the medium as a result of the converse flexoelectric effect. It is reported experimentally by Petrov et al. that the presence of SWCNTs enhances the curvature orientation and its polarisation. We discussed the case theoretically and calculated the variations of the mentioned physical properties through doping with SWCNTs. A generalised Maxwell-Garnett mixing rule is considered to calculate the effective permittivity of the medium and extend it to estimate the modified flexoelectric coefficients of the medium. In low concentrations of SWCNTs, the model calculates the increase of the dielectric anisotropy and flexoelectric coefficient up to twofold and fivefold, respectively, which is in good agreement with reported data by other researches.

Graphical Abstract

KEYWORDS:

• Liquid crystal
• carbon nanotube
• flexoelectric coefficients
• effective permittivity
• applied electric field

Acknowledgments

We gratefully acknowledge Dr. R. Aghbolaghi and Dr. V. Fallahi for their helpful discussions.

Disclosure statement

No potential conflict of interest was reported by the author(s).